Masteries

Offense:
25

Defense:
5

Utility:
0

jax= counter melee as dps through ad and ap.
stacking dodge to procc your counterstrike is a waste of runes due to the multiplicative system.Every third hit will activate rylai's passive, so with enough attack speed and movement speed(as supplied by this build), champions cannot escape a jax gank. If they try to kite you, use cleanse and leapstrike to catch up again.
Once you get to the hextech gunblade, you can solo baron by auto attacking.
Unless you are really fed, you will not get to the infinity edge. You would need to stack up 4080 gold in one go. Trust me though, once you get it, champs will melt from your excessive crit damage.
Flash is incredibly useful for firstblood, to get that last hit in before you overextend. Obviously flash is good for evasiveness.